Big investors are losing patience with unresponsive corporatedirectors, and they're showing it with their votes.

Shareholders have withheld 20% or more of their votes for 102directors at S&P 500 companies so far this year, the most inseven years, according to ISS Corporate Solutions, aconsulting firm specializing in corporate governance. While largelysymbolic, the votes at companies such as Wells Fargo & Co. andExxon Mobil Corp. are recognized as signals of displeasure and putpressure on boards to engage.

“Institutional investors are becoming more actively involved incommunicating displeasure through their votes,” said PeterKimball, head of advisory and client services at theconsulting firm, a unit of Institutional Shareholder Services.“Voting against directors at large-cap S&P 500 companies is away for an institution to send a signal to other, smaller companiesabout the actions that they don't like. That feedback tricklesdown.”